SMPS Repair Guide — Switch Mode Power Supply Repairing Tips

Terry Troves
9 min readSep 16, 2018

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Acquiring the proper SMPS repair guide book is actually pretty important for those who lack the experience, and know-how to successfully fix defective switching power supplies.

smps repair guide

Are you one of those inexperienced repairers who are super eager to learn the art of fixing power supplies as quickly as possible?

Okay, straight up, a downloadable SMPS repair book that is chock-full of repairing tips and step-by-step pictures, will definitely help you a great deal.

Even if you had only 1% talent in fixing up switch mode power supplies, as long as you are willing to work hard and follow the appropriate guide, you will eventually be very good at it.

Heck, you might even become a genius at it!

And that’s an undeniable fact.

Don’t believe me? Well, Mr. Genius himself, the great Albert Einstein said so!

There it is, straight from the man himself!

Who are you to refute one of the smartest men who had ever lived?

All right, All right, dumb joke. My apologies to you and to Mr. Einstein for putting words in his mouth.

But seriously though, without a well put together reference guide, things can get real bumpy. You are going to feel like as if you are working in the dark.

Troubleshooting faulty power supplies is obviously complex so you can’t simply opt for the go-in-and-hope-for -the-best approach.

So, where on earth can I find a top-draw SMPS repair guide book?

Yeah, I’ve been asked this question (or along those lines) numerous times in the past, and naturally, by newbie electronic repairers and technicians.

The answer to this simple yet pressing question can be found by following this link. You’ll finally uncover the solution to your switch mode power supply repairing problems.

Why this downloadable book?

1) It contains exhaustive info on ATX power supplies, SMPS components, how it operates, repairing instructions, and more, plus they are all written in a wonderfully detailed yet easy to understand manner.

2) Loaded with diagrams and in-depth overview in regards to the function of each switch mode power supply area i.e. primary and secondary.

how to repair switch mode power supply

3) It dramatically removes the guesswork out of troubleshooting defective power supplies because there’s plenty of juicy info and hints pertaining to every circuit function available in a SMPS, voltages, and even critical waveforms.

4) Critical safety protocols are covered in the book together with 11 troubleshooting and repair case histories. The case histories are extremely insightful. I’ve yet to find an SMPS repair guide book that offers such a fairly large number of case histories.

5) Isolating issues related to switch mode power supply can be executed in a number of ways and this book contains instructions to help you do so. The ability to isolate the source of failure/error is very beneficial because it enables you to pinpoint the problem without wasting too much time.

6) It teaches you the proper way to perform switch mode power supply voltage testing. The step-by-step process described in the book is easy to understand.

7) Here’s the biggest benefit…this SMPS repair book actually comes with one-on-one email support. Who’s providing the support? Why, the book author, Jestine Yong himself of course.

Jestine Yong Bsc UK

The guy is extremely knowledgeable in matters related to electronics repair and to top it off; he’s super helpful and very prompt when it comes to email response.

After downloading his book, I read it from cover to cover, but yet I still encountered a couple of issues which I just couldn’t figure out. I emailed Jestine and received a reply within several hours.

His reply was thorough and precise. Thanks to Jestine’s suggestions and advice, I was able to iron out those issues in just minutes.

We corresponded via email several times since then and he often responded within 24 hours.

All in all, I’m very pleased that I made the decision to download this SMPS repair guide book because initially, I was a little skeptical.

I thought the book might not be beginner-friendly.

Well, I sure am glad I was proven wrong!

Also, it should be noted that Jestine is the real deal.

By that, I mean he is actually a real-life professional electronics engineer as well as an instructor. That picture you see above is not some random nerdy looking dude (sorry Jestine!) that anyone can acquire from stock photo websites.

Like I said, he’s also an instructor and runs his own training center out of Malaysia, a country in Southeast Asia.

His training center is called Noahtech Electronics Training and he has taught and trained countless of aspiring electronics technicians/ repairers.

Here’s a picture of him teaching some of his students in class.

a class that teaches  folks how to repair smps

Here’s another picture of him posing with some of his students. Jestine’s on the far left sporting a new anti-nerd hairstyle.

So rest assured, if you get his guide, you will be in good hands.

Go here to learn more about this download-only switch mode power supply repair book by Jestine Yong.

Troubleshooting Switching Power Supply

About a year ago, I felt like going bonkers because I couldn’t find the right instructional guide for troubleshooting switching power supply.

The instructions I discovered on various websites were too confusing and waaaaaaaaay to hard to understand.

Needless to say, I was extremely disappointed and frustrated because I really wanted to learn how to troubleshoot switching power supply as quickly as possible.

But I didn’t give up my search!

Eventually my patience was rewarded in the form of a SMPS repairing guidebook which was put together by a highly experienced electronics engineer.

The engineer’s name is Jestine and he is pretty much my mentor now in all matters related to troubleshooting switching power supply.

If you are interested in detail-by-detail manual on repairing SMPS, be sure to check out his offering.

It’s in downloadable format and filled with generous amount of pictures and diagrams to help you understand things a lot better.

The thing I like most about Jestine’s SMPS repairing guidebook is that it comes with one-on-one email support.

This feature is massively helpful, especially for someone like me, who at the time, was a very much a newbie to the whole subject of how to troubleshoot switching power supply.

That is why I regarded Jestine as my personal mentor because he was pretty much hand-holding me on several occasions when I consulted him through email.

I recalled after reading his guidebook last year and putting some of the info to action, I had some questions regarding Negative Temperature Coefficient Thermistor for a switching power supply that I was working on, and he was quick to provide me with the answers to all my questions.

It’s a very informative guidebook with top notch support, so I would not hesitate to recommend it to anyone who searching for an all-inclusive tutorials for troubleshooting switching power supply.

Anyway, here’s some useful info regarding SMPS…

The Amount of Main Circuits in a Switching Power Supply

A typical switching power supply contains a total of 11 main circuits:

Bridge Circuit, Error Detection, Feedback Circuit, Input Protection & EMI Filtering Circuit, Oscillator Circuit, Power Factor Correction Circuit, Protection Circuit, Sampling Circuit, Secondary Output Voltage Circuit, Standby Circuit and finally Start-Up & Run DC circuit.

Take note that if one of the above circuits stops functioning, the entire SMPS will experience a number of issues.

The Varistor Indicator

Varistor is one of the main components in a switching power supply and it is designed to safeguard electronic item from being damaged by transient voltages which are generated by lightning.

Basically, this component helps to minimize electrical damage, thus making the electronic item a lot more reliable.

a varistor in a switch mode power supply

So how do you find out if a Varistor isn’t functioning properly?

Well, the clue lies with the top portion of the Varistor. A problematic Varistor usually has a top portion that’s dark in color and splits open.

You can easily test it by using an analogue meter with X 10 K ohm setting and check if there’s any reading.

If yes, it means that the Varistor isn’t functioning like normal.

To discover complete information on how to troubleshoot switching power supply, you really should check out this guide.

Obtain the appropriate troubleshooting SMPS guidebook, and you’ll be fixing power supplies like a veteran in no time!

How to Fix a Switch Mode Power Supply

Every time a newbie technician asks me how to fix a power supply via Skype, I would always recommend that the person invest in a good quality guide.

It’s something that will pay itself many, many times over. Knowledge is power folks.

If you plan on making a living in this line of work, you should amass as much reference material as possible regarding electronics troubleshooting and repairs.

You know, a couple years ago, I had zero knowledge about fixing defective power supplies. At the time, I was a novice technician.

Of course I wasn’t sure how to fix a power supply, so I promptly went online and downloaded this pretty thorough power supply repair manual.

It had all the tutorials, info, and screenshots which gave me a really massive head start.

I assume you might need a head start as well because let’s face it, troubleshooting and fixing switching power supplies isn’t as simple as ABC.

Here’s some advice and tips on how to fix a switch mode power supply…

1) Knowledge of Components

Make sure you familiarize yourself with the components that are available in the power supply.

When you conduct a computer power supply repair for instance, you need to be familiar with components such as power transistors, power IC, and power FET.

Aside from the above-mentioned components, a power supply, in general, also contains the following components:

switch mode transformer, filter capacitor, optoisolator IC, bridge rectifier, secondary output diodes, main fuse, secondary side filter capacitors, etc.

2) Protection Circuit

I thought I should just mention that a switch mode power supply is well preserved by what is known as protection circuit.

As the name implies, the purpose of this circuit is to protect the components that are situated within the power supply.

When something unwelcome occurs, this circuit shuts down a specific part within the power supply, or it might even shut down the whole thing.

There are a total of four widely used protection circuits:

i) OCP aka Over Current Protection
ii) SP aka Surge Protection
iii) SDP aka Thermal Shutdown Protection
iv) OVP aka Over Voltage Protection

3) Shorted Components within the Primary Side

Finding shorted components within the primary side of the power supply can be a real drag.

But if you find one, don’t stop there. Try examining the resistors as well.

Who knows, there might be an open circuit so that definitely has to be replaced.

Once you’ve replaced the affected components, look closely and see if you could find any cracked solder joints and make sure you fix them up good.

Put the things back together and perform a test to find out if the power supply is working.

Ideally, you would want to test it using the light bulb technique which you can view on page 154 of the power supply repair manual.

The manual is perfect as a reference guide for computer power supply repair; LCD and CRT monitor power supplies, LCD TVs, DVD players, and many other electronic devices that contain a switch mode power supply.

Now you can quickly and easily get in on the action and discover how to fix switch mode power supply like a long-time pro.

Go ahead and check out this SMPS repair guide. I’m a hundred percent confident that you’ll be glad you did.

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